Double blow header



Aug., 7, 1962 H. B. CHATFIELD DOUBLE BLOW HEADER A m m f INVENTOR Henry B. hatfielal 892557,92@ ,4,1m

ATTORNEYS J A R Aug. 77 i962 H. B. CHATFIELD DOUBLE BLOW HEADER 5 Sheets-Sheet 2 Filed March 9, 1960 ug. 7, 1962 H, B. CHATFIELD DOUBLE BLOW HEADER 3 Sheets-Sheet 3 Filed March 9, 1960 ATTORNEYS United States Patent .thee

' 3,@48l53 Patented Aug. 7, 1952 3,048,063 DOUBLE BLGW HEADER Henry B. Chatield, Metatio Research, 2683 Haliaday St., Santa Ana, Calif. Filed Mar. 9, 1960, Ser. No. 13,824 Claims. (Cl. 78-9) This invention relates to an improved double blow header which is adapted to manufacture a general range of bushings and sleeves characterized Iby a large diameter hole in the center thereof.

An object of the present invention is to provide an improved double blow header especially adapted to manufacture bushings and sleeves having a large diameter hole in the center in a rapid, eiciengand economical manner.

A further object of the invention is to provide a punch and die assembly which may be used with a conventional double-blow header.

Other objects and advantages of the present invention will be apparent to those skilled in the art from the following detailed description and drawings in which like numerals relate to like parts and in which:

FIGURE 1 is a cross sectional view of a double blow header of the present invention in the iirst or initial position;

FIG. 2 is a view similar to FIG. 1 in the second position in which the article has been formed by the rst punch blow;

FIG. 3 is an enlarged cross sectional view of the die assembly in the position of FIG. 2;

FIG. 4 is a cross sectional view taken along the lines 4 4 of FIG. 3 showing the ejector sleeve pin spacing arrangement; i

FIG. 5 is a view partially in cross section showing the third or finishing blow position in which the large diameter hole is formed in the article and it is formed to final shape;

FIG. 6 is a View partially in cross section showing the finished article being ejected; and y FIG. 7 is a view partially in cross section similar to FiG. 6 showing the waste slug being ejected.

According to this invention, a slug of metal is cut off in the conventional manner and is positioned over the die tooling (FIG. l), it is hit a forming blow by the first punch (FlGS. 2 and 3), the header slides to present the finishing punch to the die tooling and the article is hit a second or finishing blow by the finishing punch to form a large diameter hole in the center thereof (FIG. 5), the finished article or product (FIG. 6) is ejected, and lastly the slug formed by the materialV from the central hole is separately ejected (FIG. 7). The only material wasted in the whole operation is the slug formed in the nishing blow which provides the large diameter hole in the iinished article.

A slug ll normally of one to two diameters in length is cut off and transferred to a position in front of the die cavity as shown in FiG. yl. The ejector pin 6 is then flush with the face of the die cavity, having been retained there at the end of the previous stroke. The die itself is recessed within the die case 3@ a distance slightly greater than the total length of the slug l..

The coning or stover punch 3 then advances toward the die with the air or spring stover pin 2 eXtending'a substantial distance out from it and, as soon as this pin has contacted the cut-otf slug 1, it presses it against the ejector pin 6, thereby permitting the early retraction of the cutot knife while the spring stover pin 2 remains pressed against the slug 1. The means for cutting otfthe slug il is a conventional cutof knife and is not shown. The stover punch 3 continues to advance until it has caught up with the face of the air or spring pin 12.` and then the two, being flush, force the slug 'against' the ejector pin 6 and into the die cavity. At this point the outside diameter of the stover punch 3 is piloted by the liared mouth and close iitting internal diameter of the collet 27 in which the die itself is recessed, thereby establishing concentricity.

The coning punch has a shaped forming head 5 and a longitudinal bore Minto which the spring stover pin 2 retracts at the bottom of the forming stroke. Spring 4 in the bore 46 keeps the spring Stover pin in the work engaging position shown in FIG. 1 until the punch bottoms on the work as shown in FIG. 2. The punch 3 reciprocates in a cylindrical guide hole 2l formed in the punch `block 29.

-VAs the punch advances further it forces the slug 1 against the ejector pin 6 within the die itself. While the ejector pin 6 was forward from the ejection of the previous product or piece, the sliding block orstop 10 was placed in position behind the ejector rod 3 at the back of the header so that the ejector pin 6 extends well up into the die cavity a suiiicient distance to cause the slug to backward eXtrude down around the ejector pin 6. The center portion of the stover punch 3, including the p-in 2, causes the center of the product il to be reduced to a relatively thin web portion'dZ which is pierced or sheared out in the second blow. The web portion d2 is shown thicker than it usually is for purposes of illustration. In practice, it is made as thin as practicable.

Simultaneously with the completion of the extrusion backward around the ejector -pin 6 into the bottom of the die, the stover punch 3 causes the top of the slug to upset or flare out radially to form the flange or top portion of the product 43 and, as the stover punch bottoms, the die is completely filled to within a few thousandths of final tolerance. This is shown in FlGS. 2 and 3.

During this process, the shoulder 22 on the ejector sleeve 7 has retracted into engagement with the die heel plate 24tso that there is some backward extrusion from the face of the ejector pin 6, the amount of backward extrusion being less than the final lengthwise dimension of the product 4l.. The internal diameter of the ejector sleeve 7 is substantially equal to the diameter of the hole through the product and is a slip-t over the ejector pin 6. The face of the ejector pin 6 is preferably forward of the face of the ejector sleeve 7 by .020 to .100 of an inch, depending upon the particular product.

Next the Stover punch 3 retracts and is replaced, by a shift of the slide, by the iinishing punch 36. The finishing punch 36 has a short, bevelled cylindrical section 43 protruding from its face which is a few thousandths of an inch smaller than the internal diameter 49 of the collet 27 so that when the finishing punch comes forward, it is brought into perfect concentricity with the die case 30 and dies 33 and 34.

Having been brought into alignment by the internal diameter 49 of the collet 27 in the die, the nishing punch 36 now advances until its cylindrical nose 39 pierces the slug 4t) out of the center of the product 41. This is possible because while the punch was shifting, the block 10 behind the ejector pin 6 and ejector rod 8 was withdrawn so that it is now free to travel backward as the slug is pushed out of the product 41. However, inasmuch as it stands up closely against the bottom of the slug, completing the backward extrusion, it is impossible for this part of the piece being made to collapse or mushroom.

As the cylindrical section 39 of the punch 36 emerges from the back side of the product 41, it forces the slug 40 into the ejector sleeve 7 which has also been allowed to recede because it was only being held forward by the shoulder 20 on the ejector rod 8.

As the finishing punch 36 bottoms, it reduces the flange or top i3 of the product 41 to final dimensions and causes slight forward extrusion around the piercing punch down against the bottom of the sleeve 7 surrounding the ejector pin 6; However, this does not drive a burr out through the space between the punch section 39 and the ejector sleeve 7 because of the fact that there is a slight void caused by the ejector sleeve '7 having been held forward by the ejector rod 8 in the irst blow into which the metal that is forward extruded during the nal coining of the product can iiow. This is shown in PIG. 5.

During the withdrawal stroke of the iinishing punch, the ejector sleeve 7 is driven forward through the heavy Belleville springs 15 by the knockout bar 9 engaging the collar 12 on the ejector rod il so that the part 41 is driven out of the die without the ejector sleeve 7 or the slug lll moving inside of the ejector sleeve 7 which contain them. This is shown in FlG. 6.

When the ejector sleeve has traveled all the way forward against a stop and thereby completely ejected the iinished piece from the die, the Belleville springs by which it is driven are compressed and the additional travel of the knockout bar causes the ejector pin 6 to advance once or twice the thickness of the slug further forward, thereby ejecting the slug fill'. This is shown in FlG. 7.

The dilerential and sequential travel between the ejector pin 6 and ejector sleeve 7 is provided by the arrangement of the impact sleeve 12, collar 13 and Belleville springs 15.

The ejector pin 6 is attached to or integrally formed with the ejector rod S which is of a larger diameter than the ejector pin 6. The ejector rod 8 has a cap 11 at the back end thereof which rests against a back-up block 1li when the punch 3 bottoms on the work piece as shown in FG. 2. Back-up block l@ slides in slot 31 in the feed roll and knockout mounting block 457. The ejector sleeve 7 lits loosely over the ejector pin 6 and is prevented from retracting in the positions of FIGS. 2-5 by shoulders 2li on the ejector rod S and cooperating flange portions 22 on the ejector pin 7 and die heel plate 24.

A collar 13 is attached to the ejector pin 8 in back of the die assembly by a retaining pin 14. Fitting over this collar is an impact sleeve or cap 12 which projects forward and around the collar and engages Belleville springs 15. A spring retaining sleeve 16 rests against the other end of the Belleville springs and a spacer sleeve 17 is provided to help adjust and position the Belleville springs. A series or" spider pins 1S space the ejector sleeve 7 from the spacer sleeve 17 as desired, and accurately locate the ejector sleeve 7. The pins 18 are positioned in slots 23 formed in the die heel plate 24, this arrangement being shown in FIG. 4.

The ejector sleeve 7 is spaced from the impact sleeve 12 by the Belleville springs, retaining sleeve 16, spacer sleeve 17, and pins 18. When the impact sleeve 12 is first struck by the knockout bar 9, it is spaced from the collar 13 as shown in FIG. 2. It advances against the Belleville springs and the intermediate units to drive the ejector Sleeve 7 forward. This ejects the finished article 41 as shown in FIG. 6. As the blow of the knockout bar progresses, it compresses the Belleville springs and ultimately seats on the collar 13. This ejects the slug 4l) as shown in FIG. 7. The spacing between the collar 13 and impact sleeve 12 and compression of the Belleville springs thus provides sequential travel between the ejector sleeve and ejector pin. The knob 32 is provided on the knockout bar 9 to engage the collar 12. Regular coil springs or other spring means such as alternate layers of rubber and metal washers may be used instead of the Belleville springs.

The die assembly consists of a die block 25, a high tensile die case 3d positioned inside the die block, a die anvil Z8 positioned between the die case 341 and the backup block 2d, a collet 27, a die shim 35 and inner and outer die kmembers 33 and 3d. Frame 26 of the header supports and backs up the die block 24.

The finishing or second punch is illustrated in FIG. 5. lt comprises a stripper collar 37, a stripper spring 3? and a-orming punch head piece 39. The purpose of the stripper assembly is to keep the finished piece 41 in the die as the punch withdraws and prevent it from retracting with the head piece 39.

The forming aXis A--A is shown in FIG. l. lt should be noted that this is the axis common to the ejector rod, ejector pin, ejector sleeve, and die tooling. lt is also the anis in which the storer and finishing punches reciprocate when in the operating position.

The block 1t) against which the ejector rod 8 bottoms in normal operation is caused to move in and out of position every other stroke by suitable actuating means, such as a cam or small air cylinder. The timing of the placement and removal of this block is not critical. its travel takes place between strokes and at no time is it caused to move when it is under load. To further illustrate, it is placed behind the ejector bar, or rod when it is in the full forward position and is removed from behind it after the part has bottomed against it.

The modified double header of the present invention permits very economical production of high quality valve spring caps, lock bolt collars, ilanged bushings and similar parts. t is suitable for high volume production of either straight or tapered holes, cylindrical, hexagonal, or other shapes, in alloys capable of being cold-headed.

What l claim is:

l. ln combination, a frame, a die assembly and an ejector rod mounted ron the frame, and punch means adapted to sequentially engage work-pieces in said die assembly, an ejector pin on the die assembly end of the ejector rod with a smaller diameter than the ejector rod, an ejector sleeve iitting over said ejector pin with a slip-nt, a back-up block adapted Ito engage and disengage the other end of said ejector rod, a collar on the ejector rod between the ejector sleeve and back-up end of said ejector rod, a cap fitting over said collar with portions projecting forward therefrom toward the die assembly, a knockout bar adapted to strike said cap, spring means on said ejector rod which engage said cap and are located between said cap and the die assembly, and means spacing the forward end of said spring means from said ejector sleeve and being reciprocable along the axis of the ejector rod, said cap being spaced from said collar by said spring means in the normal posi-tion and being adapted to engage said collar only at the end of the stroke of the knock-out bar.

2. The apparatus of claim l in which the spring means comprises Belleville springs.

3. The apparatus of claim l in which the spring mean-s comprises Belleville springs and the spacing means comprises a sleeve slidably mounted on the ejector rod and at least two spider pins connecting said sleeve to the ejector sleeve.

4. In combination, a `frame, a die assembly and an ejector rod mounted on the frame, and punch means adapted to sequentially engage work-pieces in said die assembly, the improvement whichcomprises an ejector pin on the die `assembly end of the ejector rod with a smaller diameter than the ejector rod, an ejector sleeve which lits over said ejector pin with a slip-lit and has a smaller internal diameter than the ydiameter of the ejector rod so as to abut against it in a bottoming position, a block adapted to engage and disengage the other end of said ejector rod so as to positively restrain its backward movement, a collar disposed on the ejector rod between the ejector sleeve and back-up end of said ejector rod, a cap litting over said collar with portions projecting forward therefrom toward the die assembly, a knock-out bar adapted to strike said cap, spring means on said ejector rod which engage said cap and are located between said cap and the die assembly, and means separate from said ejector sleeve which provides ya positive driving connection between it and said 5 spring means, said ejector rod, ejector pin, and ejector sleeve having a common axis.

5. In combination, an ejector rod, an ejector pin on the end of the rod with a smaller diameter than the rod, an ejector sleeve slidably mounted on said ejector pin and having a smaller internal diameter than the diameter or" the ejector rod, a block for engaging and disengaging ythe other end of said ejector rod tto restrain its backward movement, a collar disposed on the ejector rod between the ejector sleeve and the end of said ejector rod, a cap tting over said collar with portions projecting forward therefrom, a knock-out bar for striking said cap, spring means on `said ejector rod for engaging said cap, and

2,328,096 Remington Aug. 31, 1943 2,396,995 Friedman Mar. 19, 1946 FOREIGN PATENTS 674,173 Great Britain June 18, 1952 1,018,950 France Jan. 14, 1953 1,108,552 France Jan. 16, 1956 

